Posted
by
samzenpus
on Thursday April 29, 2010 @06:57AM
from the what-could-go-wrong dept.

newviewmedia.com writes "Scientists at the Lawrence Livermore National Laboratory plan on using a laser the size of three football fields to set off a nuclear reaction so intense that it will make a star bloom on the surface of the Earth. If they're successful, the scientists hope to solve the global energy crisis by harnessing the energy generated by the mini-star."

Okay, no, nothing will likely go wrong (at least, nothing dangerous to anyone more than a few hundred yards from the event in the worst case scenario). But damn if this doesn't sound like the opening to the plot of a disaster movie.

As for the topic at hand, like fusion reactors the main problem will be getting MORE energy than you consume. There's no point in doing something like this if you spend 2 megawatts running the laser and only get 1.9 megawatts back from your star.

Perhaps a smarter move would be to figure out how to harness the star we already have (plus that second star the aliens created in Jupiter's orbit)

As for the topic at hand, like fusion reactors the main problem will be getting MORE energy than you consume.

Way to go captain obvious.

Perhaps a smarter move would be to figure out how to harness the star we already have

Thanks for the laugh. Even with 100% efficient orbital solar stations we would need a few million km^2 of panels just to match current energy usage. That number seemed large to me so I did a little digging and found this image [landartgenerator.org] that details electricity consumption alone. Switching to 100% solar and building a grid capable of redistributing that power from where it is generated to where it is used (nevermind orbital based power stations) would be a megaproject to dwarf every other co

1. You actually found these jokes funny in the first place.2. You impression of the humor changes just because you learned about the guys religious/political stance.3. You even care what his religious/political stance of an actor is?

That bothered me. Because I suspect the writers were really trying to draw a correlation between nuclear fusion and the "fusion" of the Doc's device to his spine. Clearly the fact that we use the same word for both indicates that one can cause the other... Sigh.

How about the Nuclear Regulatory Commission allowing OZ Corp to perform their test in New York City (population 8 million)? You can do all sorts of wierd physics in a superhero movie, but don't tell me bureaucracy doesn't still exist.

Riiiight... A supernova occurs when a star reaches crticle mass (it burns up untill it reaches the last remaining mass), and then all the remaining chemicals burn all at once causing the explosion and uber death and... right....

Where was I? Oh yeah; when the mass in the experiment burns up there will be no remaining mass and even if it does it soooooooooooooooooo tiny and has sooooooooooo much low amount of mass that it will not even have the impact of a grenade.

It is worth mentioning that the mini-star only has enough fuel to burn for a fraction of a second. To make an actual fusion reactor from this technology, one would need to create several of them every second. Also, even making *one* of these things ignite is really, really hard, so if your technology breaks down then your reactor stops creating new mini-stars and simply shuts down.

The National Ignition Facility is not doing research into energy production. The research they're doing will not have applications in energy production. The hope is that by understanding ignition other nuclear fusion projects will be able to make better progress.. it is completely pure research, as you would expect from a national laboratory.

Well, I'm sure the researchers are pumping it up a bit to grab funding. They did a good job of it too because it sounds awesome.

Part of the reason for saying that they are "bringing star power to earth" is likely that ever since the cold fusion hype and subsequent failure researchers avoid doing research on fusion and try to use other terms to describe what they're doing. There have been attempts like this for a while so it's nothing too new, but it is probably the most well-informed, well-funded and well

Are we not allowed to over hype anything, ever? Half the posts here read like "pfff the sun is way more powerful, this thing blows". It's an massive frigging laser, what more do people want? This research project is probably like a wet dream come true for any scientist that ever played with matches when they were a kid.

I suspect that plants do not use 100% of available energy reaching the surface of the Earth.

Correct.
Crop plants typically convert 1-2% of the sunlight striking them to biomass.
Under optimal conditions,
some varieties of sugarcane can convert up to 8%.

Its not like we'll be coating the surface of the Earth with solar panels within the next 100 years.

Nor need to.
The usual rough figure for PV solar to provide for current US electricity consumption
is about 10,000 square miles of Southwestern desert --
a square 100 miles on a side.
Of course,
you'd also need enormous changes in the national transmission grid,
and you'd have to find places to store a bunch of the daytime production
for use at night
(lots of pumped hydro storage located around the country might work for that).

I do agree, however, with your concerns about the effect of wide adoption of solar energy on weather patterns.

I suspect that we can do almost anything we want
to a 100-mile square of desert
with little or no change on climate or weather
except in that immediate area.

The resulting fusion reaction will release many times more energy than the laser energy required to initiate the reaction. Experiments conducted on NIF will make significant contributions to national and global security, could lead to practical fusion energy, and will help the nation maintain its leadership in basic science and technology.

The goal of this kind of experience is geared toward energy production. Granted, this is not a prototype power plant, but one could consider the lasers used there as a prototype for elements of a power plant.

The summary also is funny in how it understates achievements of fusion research. I remember a physicist saying "The Sun ? Pfah ! Too cold and too inefficient ! If we were to reproduce the conditionss in the sun, we would never get anything that would interest industries !"

I remember a physicist saying "The Sun ? Pfah ! Too cold and too inefficient ! If we were to reproduce the conditionss in the sun, we would never get anything that would interest industries !"

Indeed. From Wikipedia:

The energy production per unit time (power) produced by fusion in the core varies with distance from the solar center. At the center of the sun, fusion power is estimated by model to be about 276.5 watts/m3, a power production density which more nearly approximates reptile metabolism than a thermonuclear bomb. Peak power production in the Sun has been compared to the volumetric heats generated in an active compost heap. The tremendous power output of the Sun is not due to its high power per volume, but instead due to its large size.

I was reading a book about metabolic biochemistry the other day (thrilling! really!) and the author went through a series of calculations to show that mitochondria produce about four orders of magnitude more power per unit volume than the sun. I guess it's not that weird, though: the sun's predicted to live for 20 billion years, so it can't be burning *that* fast. It just seems surprising.

To be fair, a random bunch of dirt doesn't make much heat, but put a few million (billion?) cubic miles of the stuff together, and you get a molten core, a thin layer of solidified crust penetrated with volcanos, etc.

I recall reading that the NIF is the first stage of a prototype for an actual method of producing steady thermal power from fusion, i.e. a viable electricity source. After proving that the ignition occurs, the next steps are to find a way to mass produce the little fuel pellets, and then to find a way to be able to load and position the pellets fast enough and accurately enough to provide a sustained heat source (since each one lasts about a nanosecond).

> I recall reading that the NIF is the first stage of a prototype> for an actual method of producing steady thermal power> from fusion, i.e. a viable electricity source.

LLNL has been saying this for years, but it's never been true.

The primary purpose of the NIF is to give the bomb-making establishment something to do so all the physicists won't find real jobs. I am not making this up, it's well recorded and easy to verify.

The justification they release into the defence establishment is that NIF will be used to tune the hydrodynamics code they use to design h-bombs. Everyone outside LLNL dismisses the need for such a project, and the other weapons labs (like LANL and Sandia) have been particularly scathing.

To the public, LLNL releases a stream of reports about "unlimited power" and such, but calculations made over 30 years ago demonstrated there is no hope for this. At best, with completely new solid-state drivers, you might be able to get 1/10th the power out that you put in, BEFORE conversion from thermal to electrical.... with the current designs. Look up HiPER.

"The National Ignition Facility is not doing research into energy production." - True

"The research they're doing will not have applications in energy production." - If there's one thing that is constant in the history of science it's that nobody can second guess what fruits fundemental research will bear.

The National Ignition Facility is not doing research into energy production. The research they're doing will not have applications in energy production. The hope is that by understanding ignition other nuclear fusion projects will be able to make better progress.. it is completely pure research, as you would expect from a national laboratory.

My understanding from friends who work at LLNL is that it's an open secret that at the NIF they are not working on energy production, but, rather, thermonuclear ignition for weapons research. It's still pure research, in that they're working to produce controlled thermonuclear fusion rather than designing bombs outright, but the purpose of understanding fusion per se is so that we can better understand the current state of our present arsenal as it gets older. At least that's what they tell me.

So, we have a tiered layer of secrecy about NIF:

1. for the public: we're doing energy research for a petroleum-free tomorrow2. for people who probe: we're doing fusion research to model our ageing weapons stockpile3. [ guess the real reason here ]

I'm betting the third line is only marginally related to the first two, given the history of activity at LLNL.

If by "pure research" you mean "nuclear weapons research," then you are absolutely correct. I am a nuclear physicist who has done some work for the NIF project. This is a big make-work project for otherwise the otherwise unemployed nuclear weapons establishment. We don't explode nuclear weapons at the Nevada Test Site anymore, but DOE wants to make sure that we can be confident that our aging stockpile of warheads will continue to operate.

Part of the project's justification is its potential use as a scientific user facility. A big pulse of 14 MeV neutrons could be valuable for all kinds of nuclear science experiments. But that's a sideshow. Another part of the project's justification is the potential of inertia driven fusion as an energy source. To get a 600 MWe power plant out of NIF, you'd have to implode a capsule something like 10 times per second. That would involve dropping a stream of target pellets into the chamber and having the lasers target them, and hit a falling object simultaneously. Right now, the targets are individually placed at the precise center of the chamber and the lasers are fixed to aim at that point. NIF will fire perhaps twice per day once they get the bugs shaked out, and the laser people convince themselves that the lasers won't destroy themselves each time they are activated.

Assuming we can overcome those hurdles, then we have the problem of converting a burst of 14 MeV neutrons into usable energy. In a fission reactor, the (charged) fission products carry most of the energy. Being charged, they interact strongly with the fuel. Collisions transfer the energy to the fuel, the fuel heats up, and the flowing water removes the heat from the fuel to make steam and turn a generator. How do you get those uncharged neutrons to deposit their energy in a small volume of material (diffuse heat is useless heat)? Several solution have been proposed, but there are potential problems with each of them.

Assuming those problems can be fixed, where are you planning to get enough tritium to fuel the thing? NIF's Ignition Campaign is centered around D+T fusion. Tritium is a byproduct of fission reactor operations, but if you need a multi-billion-dollar fission reactor (1,110 MWe) to supply a multi-billion-dollar fusion reactor (600 MWe) with fuel... why not just build two fission reactors and devote the savings to reprocessing or disposing of the spent nuclear fuel?

The research they're doing will not have applications in energy production.

Yes it will. [llnl.gov] However, it is worth mentioning that this is only one of its three missions [llnl.gov], and most likely the main reason that this massive multi-billion dollar project received funding from Congress was so that we could we can understand fusion reactions well enough that we can model the inside of nuclear weapons and not have to test them, seeing as how we don't like testing nuclear weapons anymore.

Indeed, reaching temperatures of 65keV now, at currents half those of previous experiments ; apparently they can ignite a pB11 mix if they can get it to 100keV.

I have more confidence in their project than NIF, which is just a giant weapon simulator. Their design has some engineering elegance. Should they demonstrate over-unity, I will throw one hell of a party, and happily put up with having to explain why to all the invitees.

The March 2010 edition of Scientific American has an article [scientificamerican.com] that raises some significant doubt that we will ever be able to use fusion as a commercial source of power. The problems aren't about ignition, they are more fundamental engineering problems...

This article concentrates on Deuterium-Tritium fusion, and I agree with it in that context.

Most of the concerns are addressed by the design of a DPF reactor.

withstand temperatures of millions of degrees for years on end

That's just FUD, I'm afraid. Even in tokamak reactors, the plasma is kept separate from the reactor vessel. The plasma is at millions of degrees ; the reactor vessel is not. In a DPF reactor, the plasma is a teensy little 12 microns across - even if the contents are running at about a billion Kelvin, they won't heat the reactor vessel to millions of degrees. The reactor is also designed to emit most of it's energy through non-thermal vectors.

constantly bombarded by high-energy nuclear particles

True, in a DT reactor. Not so true in a pB reactor - the reaction produces helium and electrons, not neutrons.

has to make its own nuclear fuel

This one is the big winner. As they rightly noted, tritium is one of the rarest elements on Earth. A pB reaction uses no tritium, it uses common or garden "normal" hydrogen, and boron, an element that's abundant enough to sell as eyewash.

no outages, interruptions or mishaps—for decades on end

When a 1 GW reactor goes offline, yes, you have a shortfall problem. When the proposed 5MW output DPF reactor goes offline for it's routine maintenance (for about 12 hours), you just lean on the others you have running. Lots of small, local, redundant reactors the size of shipping containers make for more reliability than a few whacking great behemoths the size of aircraft carriers. When they cost $300,000 instead of $10,000,000,000, you can afford to pile them high, and sell them cheap.

must also convert energy from the neutrons into heat that drives a turbine

The design is intended to use 2 methods of direct energy collection that are not heat engines, a more elegant and efficient solution that places it closer to "power plant" break-even.

At least they report the purpose of NIF correctly, albeit couched in soft language - it's about "National Security", not energy generation.

Nah. Fusion power is supposed to be perpetually 10 or 20 years away. They made a big mistake with that deadline; with a mere two year timeline, people will actually remember what was promised when the deadline passes.

Well, they just had that damning report into their management, so they probably feel like they're under pressure to produce results. Thus the "confidence" that they'll be able to show something Real Soon Now.

Oh, no, not this year. We'll need at least another year of funding before they can show, well, anything.

Also, read on:

It will take at least another 20 years, with adequate funding, to develop a continuous fusion reaction

Maybe it's just my Los Angeles upbringing, but I don't see any way even a future (more efficient) fusion plant is going to generate enough energy to compensate for using up three football fields worth of urban real estate, and that's just for the ignition laser. I can only assume the plan is to build these out in the desert and transmit the electricity in...then of course tear it down and rebuild further out when urban sprawl makes more demands of the now-not-so-remote land.

Conveniently, situations that involve absolutely titanic amounts of power being generated in one place, and needing to be shipped somewhere else, are exactly the sort of thing where using superconductive lines becomes economically practical...

If you've ever visited LLNL you would know that its over the hills from Oakland/Hayward, effectively in the Imperial Valley -- where there is lots of land to build things on (which is why it takes up football fields). Now on the other hand if you one was building it in Manhattan you would go down and not out (think of the foundations for the World Trade Center buildings. The arrangement of the lasers is fairly arbitrary -- one can go down or up nearly as easily as spreading out.

The big problems concern engineering -- how to turn a piece of very expensive scientific equipment into a cost-effective and reliable power station. The challenges are huge, and not just for inertially-confined fusion, but magnetically confined fusion as well.

I'm 30 and I'm not even sure I'll be alive to see a working fusion power plant.

Hey, don't complain - usually we just link to a blog, which links to another blog linking a twitter feed with a tinurl-obfuscated link to another blog finally linking to a tabloid article. When you worked yourself through that link chain, you have all the information you need to google for the original source, which, of course, is behind a paywall.

Despite it's earlier mention in the thread, I have to take the opportunity to point out that Focus Fusion [focusfusion.org] involves a reactor design that extracts power from the reaction via 2 routes ;

Direct induction of current by a stream of helium ions

Gamma-voltaic collector

Both of which are very much more direct than steam generation. I believe the reaction has plenty of waste heat which could be used industrially as well.

Any why not? Water is a very useful working fluid - relatively high SHC, liquid at standard pressure and temperature, non-toxic, non-corrosive, plentiful, cheap.

Using it to generate electricity from heat and expansion is effective and well understood. Just because we've been doing it since the early days of industrialisation doesn't mean we have to abandon it just because it "feels a little old". It's not like a pentium 2 with a 16Mb graphics card.

All power plants that generate power from heat use steam turbines. The rest use something else to turn the turbines. There's only solar power that converts light directly into electricity without having to spin some turbines.
There aren't too many ways of generating electricity from heat. There's this: http://en.wikipedia.org/wiki/Thermoelectric_effect [wikipedia.org] but it's not nearly as efficient. If you come up with a better way you can change the world.

By "mini-star" they just mean a brief fusion reaction that is expected to last for a fraction of a second --- if for no other reason then there is only a limited amount of fuel available to it.

Also, the way in which many of those involved ultimately intend to use this is not to create a reactor drawing power purely from fusion but rather to create fusion/fission hybrid reactor in which neutrons from the fusion reaction drive fission reactions in nuclear fuel that would not become critical by itself --- i.e., so we can burn things like nuclear waste and thorium. Such a reactor would be intrinsically fail-safe because when fuel pellets stop being dropped into the reactor and ignited by lasers into "mini-stars" (which, again, is something that needs to be done continuously --- several times a second --- since the "mini-stars" burn up all their hydrogen fuel so quickly) then eventually the whole thing shuts down on its own.

In other words, this is completely unlike the ridiculous and highly implausible fusion reactor featured in Spider-Man 2 which had the magic power to sustain itself by eating everything around it --- which, incidentally, is a power that even our own *actual* sun doesn’t come close to having, since it can only burn its limited supply of hydrogen fuel.

Solar thermal power plants. Cheap as hell, nearly exclusively out of abundant and renewable materials, can be placed in any desert, and 300 km^2 of them would provide all the energy all of humanity would need. Any 3rd world country could do with them.

Of course they won’t work in the night, and be weaker where there is less sun. But we have enough energy storage solutions. The best of those are hydroelectric dams in colder regions, where you use the excess energy to pump water upwards, and can release

Yeah, that's about right. Last time I worked the numbers we'd need to cover 1/4 of New Mexico to do it right. More if you assume less than 100% coverage to allow for service aisles, and out-of-order allowances.

The trouble is, that's the largest engineering project humanity has ever undertaken. And there's no water in New Mexico to store the energy. Up north we have the water, but not enough sunlight.

Super idea. Lets build a second sun on earth so we can use the energy to drive some turbine technology we already have. This is a great idea. OK it is not working right now and other promising projects like ITER will not show any benefits before 2060, but I think we should wait for their development. Why waste money on a heterogeneous and distributed energy system, which have so many component that can fail.

Of course todays solar and wind technology works and it is available and when something goes wrong we

A real fusion powerplant is the size of a trashcan and accepts any old garbage you have around as fuel. Puts out gigawatts of power.

Yeah, they might eventually fry a few teensy pellets at the NIF, but I mean really - huge impractical lasers perfectly synchronized onto tiny hard-to-make fuel pellets fed at precisely the right rate and positioned in precisely the right place at precisely the right instant to be imploded? Operating perfectly over months and years in industrial powerplant conditions? Maintain

"The world needs to employ existing fixes for climate change rather than looking for a technological silver bullet that will prove to be too expensive for commercial energy production anyway"

Actually, the world really ought to be doing both. I'm not implying the existence of a "silver bullet" but any renewable energy source (especially one as fundamental as solar fusion) is probably a worthwhile endeavor. Just because it isn't immediately commercially viable doesn't mean we can't still benefit from it.

"It will take at least another 20 years, with adequate funding, to develop a continuous fusion reaction thatcould heat water, create steam and turn generators at a commercial fusion power plant, she said."

The problem with fusion is not that it's hard to make it stop, it's hard to maintain it.If something goes wrong, you don't get any reaction. That's about it.There's only so much deuterium & tritium available during the reaction (cf http://en.wikipedia.org/wiki/File:Fusion_microcapsule.jpg [wikipedia.org]).